Optical Imaging System

Abstract

An illumination device for an optical imaging apparatus, such as a microscope. The illumination of a slide specimen is achieved when divergent light for a point light source or a plurality of point light sources illuminate the specimen converging at high angles at equal brightness across all angles. The user of divergent light cancels the cosine distributed gradient effect (Lambert's cosine law) to effectively create a substantially evenly distribution of light. The placement of diffractive or diffusive film under the specimen causes the light to converge at high angles onto the specimen. The light from the point light source can be further diffused by passing it through a column having its interior coated with a non-diffractive material adapted to widely scatter the light.

1 . An optical imaging system comprising:
 a film affixed a distance from a slide, the film being illuminated from an imposing direction by at least one LED such that a slide sample to be imaged receives even illumination across its width and through a range of angles defined by a numerical aperture of the optical imaging system.   
   
   
       2 . The optical imaging system of  claim 1 , wherein the film is a diffractive film. 
   
   
       3 . The optical imaging system of  claim 1 , wherein the film is a diffuser film. 
   
   
       4 . The optical imaging system of  claim 3 , wherein the film is a holographic wide angle diffuser film. 
   
   
       5 . The optical imaging system of  claim 1  further comprising an array of LEDs, wherein said LED array is designed such that individual Lambertian light cones superpose to create substantially constant, even illumination to an underside of a holographic wide angle diffuser film. 
   
   
       6 . The optical imaging system of  claim 1 , wherein said film is illuminated by the at least one LED covered by a columnar diffuser. 
   
   
       7 . The optical imaging system of  claim 6 , wherein the at least one LED is a side-emitting LED placed on a reflective surface. 
   
   
       8 . The optical imaging system of  claim 6 , wherein an interior surface of the columnar diffuser a non-diffractive material adapted to widely scatter the light from the at least one LED. 
   
   
       9 . The optical imaging system of  claim 8 , wherein the non-diffractive material is titanium dioxide. 
   
   
       10 . The optical imaging system of  claim 1 , wherein said numerical aperture is at least 0.95. 
   
   
       11 . A method of optical imaging comprising:
 affixing a wide angle diffuser film a distance from a microscope slide, wherein the wide angle diffuser film is positioned between the microscope slide and an LED or array of LEDs;   emitting light from the LED or the array of LEDs, wherein the emission of light generates a substantially even illumination from the diffuser film;   illuminating the microscope slide with the substantially even illumination across a specified width and through a range of angles as defined by a numerical aperture of an optical system employed with said wide angle diffuser film.   
   
   
       12 . The method of  claim 11 , wherein the wide angle diffuser film comprises holographic wide angle diffuser film. 
   
   
       13 . The method of  claim 11 , wherein said LED array is designed such that individual Lambertian light cones superpose to create substantially constant, even illumination to the wide angle diffuser film. 
   
   
       14 . The method of  claim 11 , wherein said wide angle diffuser film is illuminated by ring illumination from an LED or array of LEDs covered by a columnar diffuser, wherein a slide sample to be imaged is illuminated evenly across its width and through the range of angles. 
   
   
       15 . The method of  claim 14 , wherein the ring illumination is produced from at least one side emitting LED placed on a reflective surface with the columnar diffuser placed thereover. 
   
   
       16 . The method of  claim 14 , wherein the columnar diffuser is adapted to bounce light off and into an underside of the wide angle diffuser film. 
   
   
       17 . The method of  claim 11 , wherein the numerical aperture is at least 0.95. 
   
   
       18 . The method of  claim 17 , wherein said numerical aperture of at least 0.95 is obtained by light entering from 0° to 72° normal to an underside portion of said slide sample. 
   
   
       19 . The method of  claim 11 , wherein even illumination eliminates a requirement for said optical system to be centered or adjusted for different slide samples.